The problem with adding a top wire to your 43 foot vertical is that it
is probably not made to support a wire pulling on it at the top,
unless it's cross section is uniform and it is guyed at the mid-point
and top so it doesn't pull over. What is often done in this situation
is that a trap is employed at the top between the vertical and wire so
any RF above 160 m. doesn't make it to the wire. That was the HyGain
HyTower 160 m. add-on kit design.
Or, you can use the 43 foot vertical (if it is strong enough) to hold
a separate wire on insulated standoffs for 160 and feed the wire at
the base for 160. I do that with my 1/4 w. 80 m. vertical; the
inverted L wire is about 3 feet out from the 80 m. mast. To be
honest, I recommend something like that for 160 and 80 m., over the
same ground system, with some other solution for 40 on up. I'm not a
big fan of the 43 foot vertical which has some strange fascination for
many hams.
73
Rob
K5UJ
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